The present invention relates to a reed for a high-speed loom and, more particularly, to a reed for a high-speed loom which has reed blades coated with a hard film in order to increase their resistance to wear.
A reed is a component of a loom used to align and press the warps and wefts, respectively, of the loom, thereby straightening the weave pattern. The reed is formed by arranging a large number of reed blades, each comprising a thin metal plate, parallel to each other at small gaps, and attaching the blades to a frame having right and left side master blades and upper and lower metal portions. In a high-speed loom, reed blades made of stainless steel are generally used. However, due to increases in the operating speeds of looms and the introduction of new material fibers, wear of the reed blades has become severe. Increasing the wear resistance of reed blades poses an important problem.
More specifically, wear of the reed blades causes raising of the woven fabric and end breakage. Because replacement of the reed requires a large amount of labor and cost, the durability of the reed blades is the most significant factor that determines the operating efficiency and cost of the loom. In a woven fabric, since the width of the woven fabric becomes smaller than the total width of the arranged warps to cause a phenomenon called "crimp", an especially large frictional force acts on the reed blades arranged in the vicinities of the two sides of the reed. Hence, the durability of these portions determines the service life of the entire reed.
Therefore, in order to improve the durability of the reed, it is proposed to coat the surfaces of the reed blades, especially in the vicinities of the two sides of the reed, with a hard film which has an excellent wear resistance, e.g., a hard chrome plating film, a ceramic film (Japanese Patent Laid-Open No. 60-52658) made of tungsten carbide, titanium carbide, titanium nitride or the like, or a chrome oxide film (Japanese Patent Laid-Open No. 61-245346, and U.S. Pat. No. 4,822,662).
A hard chrome plating film is formed by electroplating. However, the hard chrome plating film has poor wear resistance as well as poor adhesive properties and corrosion resistance. A ceramic film is formed in accordance with Physical Vapor Deposition (PVD), Chemical Vapor Deposition (CVD), flame spraying, or the like. However, the ceramic film has poor adhesive properties and causes softening of the base material upon high temperature treatment. A chrome oxide film is formed thermochemically and is effective when formed on reed blades for use with polyester fibers. However, the chrome oxide film is not sufficiently effective when formed on reed blades for use with natural or new material fibers.
Wear of the reed blades is a phenomenon in which the types of fibers, frictional force, vibration characteristics of the reed, and the like are closely related to each other in a complex manner. It is known that a hard film having a high surface hardness does not always provide a good effect. Accordingly, although a hard film matched with the types of fibers, the operating speed of the loom, and other conditions is employed, it provides an improvement in durability of only about two to five times that of a stainless steel base material not coated with a hard film.